By Anthony Capkun
September 9, 2013 – Already noted for saving gasoline and boasting zero emissions, electric cars have quietly taken on an unlikely new dimension, said electric vehicle (EV) pioneer John E. Waters: the ability to reach speeds rivalling the 0-to-60 performance of a typical Porsche or BMW, and compete on some courses with the world’s best gasoline-powered cars.
Speaking at the 246th national meeting & exposition of the American Chemical Society (ACS), Waters said relatively recent advances in engineering and use of lithium-ion batteries are producing EVs capable of leaving traditional internal combustion engine race cars in the dust.
“Experimental electric cars already have achieved sustained speeds of more than 180 mph, and established world speed records above 300 mph,” said Waters. “Electric cars have inherent advantages in efficiency and torque over gasoline-powered vehicles. Energy storage-to-torque on an EV platform is above 90% efficient, compared to less than 35% for internal combustion engines. I have no doubt that battery-powered race cars will be attracting race fans in the immediate future.”
Waters pointed out that race cars and racetracks do more than thrill an estimated 90 million motorsport fans in the United States alone. In addition, they have served historically as test beds for new automotive technology, the place where top-notch performance fosters wider public acceptance of the technology to be found eventually in consumer cars. That is proving true as EVs attain “breathtaking speeds”, puncturing myths about (slow) EV performance.
Electric race cars have such a great capacity for speed because they utilize energy more efficiently than internal combustion engines, Waters explained. Turning gasoline into motion involves multiple steps that transfer motion from pistons to a crank shaft, to a flywheel, through a transmission and other mechanisms to finally reach the wheels. Each step consumes energy before it can become applied as torque to the wheels.
In an EV, the conversion is more direct, from batteries to an electric motor that operates with “negligible friction” (electric motor still goes through a simplified gearbox and other mechanisms to the wheels). EV motors often provide up to 15,000 rpm compared to less than 8000 rpm for internal combustion engines (consumer cars usually provide less than 6000). The high rpm of the electric motor eliminates the need for heavy and expensive transmissions.
The bottom line, Waters said, is that EVs have “instant torque”, which has enabled test cars to zip from 0-to-60 mph in less than 4 seconds. Waters said, “It’s hard to believe unless you experience it. Every Tesla owner knows what I am talking about.”
A limiting factor for electric race cars on oval courses is sustaining speeds over 150 mph. Due to the tremendous energy consumed to overcome aerodynamic drag at those speeds, current lithium batteries could only last about 10 minutes before a pit stop, Waters pointed out.
“Racing in excess of 150 mph on high-speed ovals will take a significant breakthrough in battery technology for EV race cars, or racetracks, to be competitive in the Indianapolis 500 or NASCAR events,” Waters said. There has been some discussion about modifying oval racetracks so that EV race cars could actually charge their batteries while racing.
Road-course racing, which takes place on real streets with turns and a lot of braking, however, is another matter. Technology such as regenerative braking, which recovers energy to recharge the battery, means the EVs can race from 0 to 150 mph for about 35 minutes, which is a comparable racing time to internal combustion engine racing.
“With the dawn of new and advanced energy storage, we will soon see supercars—electric race cars with instant torque—that accelerate in a blink of an eye and reach top speeds of 200 mph or more,” concluded Waters.